Linq vs Fill

using System;
using System.Collections.Generic;
using System.Linq;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Attributes.Columns;
using BenchmarkDotNet.Attributes.Exporters;
using BenchmarkDotNet.Attributes.Jobs;
using BenchmarkDotNet.Running;

namespace Sandbox
{
    [ClrJob] [RPlotExporter, RankColumn]
    public class LinqVsFill
    {
        private string[] _values;

        [Params(1000, 10000, 50000, 100000, 150000, 200000)]
        public int N;

        [GlobalSetup]
        public void Setup()
        {
            _values = new string[N];

            var random = new Random(42);

            for (int i = 0; i < N; i++)
            {
                _values[i] = DateTime.Now.ToString() + random.Next();
            }
        }

        private IEnumerable<string> FilterLinq()
        {
            return from a in _values where a.Contains("7") select a;
        }

        private List<string> FilterFill()
        {
            var result = new List<string>();

            foreach (var a in _values)
            {
                if (a.Contains("7"))
                {
                    result.Add(a);
                }
            }

            return result;
        }

        [Benchmark]
        public int Linq()
        {
            var count = 0;

            foreach (var value in FilterLinq())
            {
                count += value.Length;
            }

            return count;
        }

        [Benchmark]
        public int Fill()
        {
            int count = 0;

            foreach (var value in FilterFill())
            {
                count += value.Length;
            }

            return count;
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            var summary = BenchmarkRunner.Run<LinqVsFill>();
        }
    }
}